As Jim has, I've moved my timing around on everything from my converted SuperTigre 51 all the way up to my DLE55 and found NO gain in rpm's after 30 degrees and sometimes it even falls off before I get to 36. The 50cc stuff starts kicking back a lot when you get up around 40. I set all mine at 28-30 now. I've done the research for myself and see no need for any more. (with the exception of my four stroke conversions which are a completely different animal altogether.)